I remember seeing this movie as a kid some time in the late 80s, maybe early 90s (video rental). It's been a weird movie mixing space/science fiction and fantasy elements. The whole movie didn't take itself very serious.

The basic promise has been some good guys vs. an empire thingy (similar to Star Wars).

I only remember the following details:

Strongest memory: Later on the evil guys control a planet or asteroid with some kind of giant engines attached, allowing them to move the whole thing.

Early in the movie there's some kind of space chase. One of the heroes tries to get away from some kind of "space police" (i.e. some kind of fighter with attached flashing lights and some kind of police siren).

Some time into the movie one character visits some lone house on a planet (I think seen as a silhouette with a tree next to it) being inhabited by some kind of witch to obtain some poison or whatever.

You're correct. Checked on YouTube (youtube.com/watch?v=_O7mOl5KkEw) and it's clearly the movie I remember. Didn't know it's been from Japan, but I clearly remember the main villain with his bleak face.
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MarioDec 24 '12 at 22:48

@Mario - Your question actually inspired me to watch it again, and luckily I found it on Netflix. Thanks!
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System DownDec 24 '12 at 23:45